This disclosure relates generally to photoemission structures, and particularly to scalable photoemissive structures that are integrated in a semiconductor structure with a laser/light emitting source, and a method of making scalable photoemissive structures using CMOS semiconductor manufacturing techniques.
Photoemission is a process of extracting electrons or similar particle beams from a photoemissive material (e.g., metal, semiconductor, insulator) by using light (e.g., UV, Visible, IR). A major factor in this process is the use of efficient photoemissive structures to collect and concentrate the incident light.
A major problem for these structures is being manufacturable and scalable (in number and size) at the same time. Most prior art photoemitters are not manufacturable nor are they scalable to any great extent.
Moreover, some of the light sources have a common light source which can cause unnecessary heating of the surrounding substrate.
Some current architectures use a single electron source (Thermal Field Emission or Cold Field Emission) and split it into multiple beamlets. Current at the wafer level which translates into charge delivered, is a major throughput limiting factor for particle beam based lithography. The maximum current achievable by a single source is limited by space charge effects.
As throughput is a major challenge for particle beam based lithography due to serial nature of the process, to address these issues, multi-beam tools are currently being pursued. However, other drawbacks of the aforementioned architectures include system complexity and scalability.